>US backed off last year when there were talks about protecting Taiwan. They pulled Patriot missiles from Taiwan and South Korea too.
>US cannot blockade Hormuz, as we've seen. JP cannot do that with their current constitution unless they change it (the current government is on the road to it, though).
If China really wants to fuck with Taiwan, they had better do it soon while the most incompetent US administration ever to hold office is still there. Because there is change coming to the US and the next president isn't likely to be such a complete moron.